I'm confident that there would be a gas phase catalytic method.  Try the literature.

Thank you. My access to literature is limited. From what I have been able to find it looks like it might require a two step process, N2 --> NO2 --> N2O, because the enthalpy of N2+O2 --> N2O is more than twice that of N2+O2 --> N2O2. I'm thinking that the first step of the Haber process, with O2 instead of N2, would work to get N2O2, which could then be reduced to N2O using a process I did find in the literature. What I so far have not been able to find is a one-step process that produces N2O directly.